Reed relay switching networks



Dec 5, 1967 M. M. ROUZIER ETAL REED RELAY SWITCHING NETWORKS 2 Sheets-Sheet l Filed July l2, 1966 ISIQ :Y R Q INVENTORS Michel M. ROUZIER 8c Henri P. MARNAT r' ey Atto Dec. 5, 1967 M. M. ROUZIER ETAL 3,356,973

REED RELAY SWITCHING NETWORKS l Filed July'lz, 196e 2 sheets-sheet 2 Michel M. ROUZIER 8c Henri P. MARNA'I W4 Mfg Attorney United States Patent O 3,356,973 REED RELAY SWITCHING NETWORKS Michel M. Rouzier, 15 Chemin de la Sabliere, Vauhallan 78, France, and Henri P. Marnat, Chaperon Vert, 4th

Ave., Gentilly 94, France Filed .luly 12, 1966, Ser. No. 564,575 Claims priority, applicatign France, July 17, 1965, 25 37 2 claims. (l. sas- 112) ABSTRACT F THE DISCLOSURE control wire and said column control wire and the point of junction of said control reed relay and common winding being connected to the supplementary row control wire. Connection signals are selectively applied between one supplementary row control wire and one column control wire of the matrix through a common winding and holding signals are selectively applied between one principal row control wire and one column control wire through the operated control reed relay and the common Winding.

The present invention relates to electronically controlled electromechanical switching networks and more particularly to switching networks wherein the crosspoints are constituted by a plurality of reed relays having a common energizing winding.

In particular, through the article by H. Schonemeyer entitled The experimental Stuttgart Exchange, rst application of the quasi-electronic HE60` switching system and published in the Revue des Tlcommunications vol. 32, No. 2 (1964) pages 253 to 270, switching networks are known which comprise matrices, the crosspoints of which are constituted by pluralities of reed relays having a common energizing winding. These crosspoints are controlled by reed relays associated with the rows and columns of said matrices and the response time of which is added to that of the reed relays constituting the crosspoints. Since the wear of the reed relays depends on the number of times their contacts are opened and closed and since the relays associated with the rows and with the columns of a matrix operate far more frequently than those which constitute the crosspoints thereof, the life of the former is much shorter than that of the latter. Moreover, in the switching network described this article, the tests for the availability of routes are effected by means of reed relays, the rate of operation of which is of the same order and the life of which is as limited as those of the reed relays controlling the crosspoints.

One object of the invention is to provide switching networks comprising matrices, the crosspoints of which are reed relays wherein the duration of the connection and disconnection operations at a crosspoint in the matrix is limited substantially to the response time of the reed relays which constitute it.

Another object of the invention is to provide a switching network with reed relays, the component members of which have a life of the same order.

One feature of the switching network of the invention ice is that the points of its switching matrices consist of pluralities of reed relays having a common energizing winding controlled directly by electronic means.

Another feature of the switching network of the invention is that each crosspoint comprises a reed relay serving as a holding contact for all the reed relays which constitute it.

Another feature of the switching network of the invention is that it comprises means for applying, to the energizing winding of each crosspoint, an operating current, means for applying to the energizing winding of an operated crosspoint, a holding current by means of said reed relay serving as a holding contact, and means for regulating independently the values of the operating and holding currents.

Another feature of the switching network of the invention is that shunt circuits for the sur-ges due to the variations in current in the energizing windings of the crosspoints are established through diodes lat the inputs to each matrix in such a manner that they electronic means controlling the crosspoints are protected from these surges and the noises which they cause through crosstalk are reduced.

One feature of the switching network of the invention is that the energizing windings for the crosspoints used in a connected route are fed in series by the holding current in such a manner that their connections between matrices can serve as test wires and that one end of said route can be identified by causing a variations in the holding current at its other end.

These features and advantages will be more clearly apparent, together with others, on reading the following description and examining the accompanying drawings in which:

FIGURE 1 is a diagram of va crosspoint with three reed relays and electronic control circuits in a matrix of a switching network according to the invention, and

FIGURE 2 illustrates diagrammatically a switching network with three matrices laccording to the invention.

FIGURE l shows a crosspoint with three reed relays 111, 211, 311 of a switching matrix 100, an operating circuit for this crosspoint comprising two transistors 41, 42 respectively controlled by a control row address register 44 and a control column address register 45, and a release circuit comprising a transistor 43 controlled by a release row address register 46.

The connection matrix lllt) is a triple matrix comprising triple rows such as 211, 221, 231 and triple columns such as 111, 121, 131, the crosspoints of which are constituted by groups of three reed relays such as 111, 211, 311 having a common control winding 3211. Two of the reed relays in each group, for example 211 and 311 respectively connect the columns 121, 13-1 and the rows 221, 231 associated with the two line wires of a telephone line and the reed relay 111 which constitutes the holding contact of the crosspoint connects the column 111 to one end 3311 of the winding 3211, the other end of which is connected to the line 211. The point 3311, which is common to the reed relay 111 and to the winding 3211, is connected by means of a diode 3111 and a resistor 30L of value R1, to the collector of the transistor 42. This is a p-n-p transistor which is controlled through its base through the output from column address register 45 asociated with the column 111 and the emitter of which is connected to ground; its collector is connected' through a bias resistor 47, shunted by a reverse diode 48, to the negative terminal, for example at -12 v., of a voltage source 35 having its midpoint connected to ground. The transistor 41 is an n-p-n transistor controlled through its base by the output from control row address register 44 associated with the row 211 having its emitter connected to the negative terminal of the voltage source 3 35 and its collector connected to the row 211. The transistor 43 is likewise of the n-p-n type; its base is connected to the output of release row address register 46 associated with the row 211, its emitter is connected to ground and its collector is connected, by means of a diode 50, to the row 211, itself connected to the positive terminal at +12 v. of the voltageI source 35, through a reverse diode 49. Furthermore, the column 111 is connected tothe same positive terminal ofthe source 35 through a resistor 40 of value R2.

In the normal condition, the transistors 41, 42 are cut off, the transistor 43- is saturated and the diode 3111 is blocked by the negative potential which is transmitted thereto through the resistors 47 and 30 in such a manner that no current can circulate in the windings 3211 and that the reed relays 111, 211, 311 remains inoperative.

In order to operate the triple crosspoint, control pulses are applied simultaneously and respectively by the registers 44 and 45, at the time t3 to the bases of the transistors 41 and 42. These become saturated, the diode 3111 is unblocked, and the appearance, at the two terminals of the Winding 3211, of the pulses obtained, gives rise to a current there which circulates in the direction from the access 3311 to the Vaccess 211 and becomes established in accordance with a transient phenomenon in a time t1 which is a function of the inductance L1 and of lthe resistance r1 of the winding 3211, and of the value R1 of the resistor 30. At the end of the time t1, this current reaches the value 12 V./ (R11-r1) which `is suiiicient to operate the three reed relays 111, 211, 311 through the path, ground, saturated transistor 42, resistor 30, diode 3111, winding 3211, saturated transistor 41, -12 v.

The operation of the relay 111 causes the appearance, in the winding 3211, of a second current having a value substantially equal to 24 v./ (R2-H1) which is temporarily superimposed on the operating current in the same direction through the route |12 v., resistor 40, column 111, reed relay 111, winding 3211, row 211, saturated transistor 41, -12 v. and then drops by half to the value 12 v./ (R24-r1) when the control pulses leaving the registers 44 and 45 come to an end, and the transistors v41 and 42 are cut off and unblock the diode 50, which closes its circuit to earth through the saturated transistor 43, at the same time as they cut the operating circuit.

The value R2 of the resistor 40 is selected in such a manner that the intensity 12 v./(R2-{r1) of the holding current is sucient to hold the reed relays 111, 211, 311 operated.

The disconnection of the crosspoint is obtained by applying a cut-oit pulse, originating from the release row address register 46, to the base of the transistor 43, the cutting off of which interrupts the return to ground of the holding circuit and reconnects this to the positive terminal of the source 35 by means of the diode 49. The transient current which then arises in the winding 3211 as a result of its inductance and travels through the circuit passing through the row 211, the diode 49, the resistor 40, the column 111 and the reed relay 111 to be closed through the winding 3211, temporarily holds the relays 11.1, 211, 311 Operated.

The law of decay of this transient current depends on the time constant L1/ (R24-r1). When the relay 111 opens, the new law of decay of this current depends on the time constant L1/(R1-i-r1), the circuit established to the terminals of the coil 3211 then being closed through the source 35, by the row 211 and the vdiode 49 on the one hand and the diode 48, the resistor 30 and the diode 3111 on the other hand.

As will be seen, since the break current of the coil 3211 always nds a closed circuit to flow away through, it cannot start any sparking between the stems of the relay 111 when their contact is opened.

In order to avoid unnecessary overloading of the drawing, only a single one of the crosspoints in the matrix 100 has been illustrated in FIGURE 1 it being understood that, in accordance with conventional arrangements, the transistor 42, the resistor 30 and the resistor 40 may be common to all the crosspoints associated with one and the same column and the transistors 41 and 43 may be common to all the crosspoints associated with one and the same row.

FIGURE 2 illustrates, by way of non-limiting example, a chain consisting of three identical matrices 101, 102, 103 which are identical with the matrix 100 in FIGURE l and the -interconnection of which enables two channels A and B to be connected to one another, each having three wires, comprising two line wires and one control and test wire.

The members common to FIGURES 1 and 2 are designated by the same reference numerals with the addition to their index, in FIGURE 2, of an additional digit 1, 2 or 3 according to whether these members are associated with the matrices 101, 102 or 103.

At the end A, the line wires are connected to the rows 2211, 2311 of the matrix 101 and the control wire to its row 2111. The columns 1111, 1211, 1311 of the crosspoint selected in the matrix 101 to ensure the connection, are connected to the rows 2112, 2212, 2312, in the matrix 102 and the columns 1112, 1212, 1312 of the crosspoint selected in the matrix 102 are connected to the rows 2113, 2213, 2313 in the matrix 103. The columns 1113, 1213, 1313 of the crosspoint selected in the matrix 103 are connected respectively to the control and line wires of the channel B.

Associated with each triple row in the matrix 101 are connection transistors 41 and disconnection transistors 43 which are controlled individually by the control row address register 44 and release row address register 46 and associated respectively with each triple column in the matrices 101, 102, 103 are transistors 421, 422, 423, associated with individual outputs of control column address registers 451, 452, 453 and resistors 301 of value R11, 302 of value R12 and 303 of value R13. Associated with the first wire 1113 of each column in the matrix 103 is a resistor 40 which connects it to the 'positive terminal of the source 35 and the first Wire 1111, 1112 of each column in the matrices 101, 102 is connected to the two terminals of the source 35 through reverse diodes 611, 621 and v612, 622. Magnetic cores 8111, 8212, 8313, the control and reading circuits of which are not illustrated, enable the passage or the absence of current to be detected in the columns such as 1111, 1112, 1113 in the matrices 101, 102, 103 in order to seek the available routes between the channels A and B for example through the three matrices 101, 102, 103 as is known, in particular, from the article by lean Duquesne and Michel Rouzier entitled A Connection Network for an Electronic Telephone Exchange which appeared in the French periodical lOnde Electrique No. 455, February 1965, pages to 211. Moreover, magnetic cores 9111 associated with each of the rows 2111 in the matrix 101 enable the identication of the channel A which is connected, through the three matrices, to a column such as 1113 in the matrix 103 by short-circuiting of the resistor 40 connecting said column to the positive terminal of the source 35, by means of transistors such as 73 controlled by an identification control register 70. An identification response register 71, the inputs of which are connected to the columns such as 1113 in the matrix 103 by means of diodes such as 72 enable the channel B to be identified which is connected to a channel A, to the row line 2111 of which there is applied a negative pulse, unblocking the associated transistor 41 by means of the register 44.

When a route such as that illustrated on FIGURE 2 between two channels A and B is available, the n-p-n transistors 41 and p-n-p transistors 421, 422, 423 and the diodes 311.11, 31112, 31113 are blocked, the n-p-n transistor 43 is saturated and the contacts of the reed relays 1111, 2111, 3111, 1112, 2112, 3112 and 1113', 2113, 3113 are Open The operation of the crosspoints of the matrices 101, 102, |103, is effected in turn by coincidence between the unblocking of the transistor 41 and that of each of the transistors 421, 422, 423 in succession. For this purpose, a time base, not illustrated, controls the moments of the beginning and end of the application of unblocking pulses to these transistors by the address registers 44,` 451, 452 and 453 respectively. These moments are calculated as a function of the inertia of the reed relays and of the time constants of their control circuits.

At the moment to, the registers 44 and 451 simultaneously unblock the transistors 41 and 421 of which the first applies a negative pulse (from to -12 v.) to one end of the winding 32111 through the row 2111, and: 'of which the second applies a positive pulse (from -12 v. to 0) to the other end 33111 of the winding 32111, through resis tor 301 and diode 31111. The resulting current only reaches its nominal operating Value 12 v./(R11+r11) at the end Of a tlflle 10=L11/(Ruir11), L11 the inductance of the winding 32111 and r11 its resistance. Since the reed relays 111, 211, 311 have a certain inertia, their contacts only close at a moment t2.

The register 452, then unblocks the transistor 422 which becomes saturated and applies a positive pulse (from -12 v. to 0) to the end 33112 of the winding 32112 of the matrix 102, while the voltage 12 v. applied by the saturated transistor 41 to the row 2111 is transmitted by the winding 32111, the reed relay 1111, the column 1111, and the row 2112 of the matrix 102 to the other end of the winding 32112. A current therefore develops in this winding in accordance with a transient phenomenon depending on the time constant far-f2:(L11iL12)/(R12i12if11) and is superimposed, in the winding 32111 of the matrix 101, on the operating current which had been established there since the time t1.

Thus at the time t3, the current in the winding 32111 `recahes an intensity substantially double that which it had from t1 to t2. The register 451 then cuts off the transistor 421 which tends to restore the intensity of the current in the winding 32111 to its previous value and the decreasing transient current which results finds a conducting path through the saturated transistor 41, the diode 621 and the reed relay 1111.

At the same moment, the operating current having a value 12 v./ (R12-f-r12-1-r11) `established in the winding 32112 operates the reed relays 1112, 2112, 3112. This operation takes place with a certain inertia from the time t3 to the time t4. The register 453 then unblocks the transistor 423 which becomes saturated and applies a positive pulse (from -12 v. to 0) to the end 33113 of the winding 32113 of the matrix 103 while the voltage -12 v`. applied by the saturated transistor 41 to the row 2111 of the matrix 101 is transmitted by the winding 32111, the reed relay 1111, the column 1111, the row 2112 of the matrix 102, the winding 32112, the reed relay 1112, the column 1112 and the row 2113 of the matrix '103, to the other end of the winding 32113. A current therefore arises in this winding in accordance with a transient phenomenon dependent on the time constant and is superimposed, in the windings 32111 and 32113 of matrices 101 and 102, on the operating current which had become established there during the time t3. At the time t5, since the current in the windings 32111, 32112 has a value substantially double that which it had from t2 to t1, the register 452 cuts off the transistor 422 which tends to restore this current to its previous value and the decreasing transient current which results finds a conducting path through the reed relay 1111, the winding 32111, the saturated transistor 41, the diode 622 and the reed relay 1112. At the same moment, the operating current of value 12 v./ (R13-i-r13-1-r12-1-r11) established in the winding 32113 foperates the reed relay I1113, 2113, 3113. This operation takes place with a certain inertia from the time t to the time t3 at the time t6, the register 44 cuts off the transistor 41 6 which has the eiect of unblocking the diode 50 and of thus bringing the row 2111 of the matrix 101 to ground potential by means of the saturated transistor 43 and the register 453 cuts off the transistor 423 which has the effect of restoring the potential of the column 1113 of the matrix 103 to +12 v. through the resistor 40 having a resistance R2. The holding current thus established has the value of Since the nominal operating currents in the windings 32111, 32112, 32113 have respective values, with a voltage of :12 volts, of

12/(R11-i-r11) (from the time t1 to the time t2) 12/(R12-i-12-i-11) (from the time f3 t0 the t4) lz/(Rlg-i-rla-i-lg-i-u) (from the time t5 t0 the time 16) and itis possible to give them the same value by taking With regard to the identification of the end A of a connected route, that is to the search of a channel A connected to a given channel B, a positive pulse is transmitted by the identification control register 70 through its terminal associated with the channel B considered to transistor 73 which becomes saturated, The magnetic core 9111 inserted in one of the wires of the channel A is so designed as not to be responsive to the holding current, but only to the -positive surge in said holding current due to the changeover of transistor 73. Accordingly, magnetic core 9111 changes over. Diode 72 prevents the identification response register 71 from being actuated. With regard to the identication of the end B of a connected route, that is to the search of a channel B connected to a given channel A, a positive pulse is transmitted by row address register 44 through its terminal associated with the channel A considered to transistor 41 which becomes saturated. A negative pulse is applied to the row 2111 of the matrix 101, which pulse is transmitted to the identication response register 71 by the connected route and the diode 72 associated wtih the column 1113 of said route.

What we claim is:

1. A switching network comprising matrices having rows including line-wires, a principal control wire and a supplementary control Wire, columns including linewires and a control wire, and cross-points each formed by line reed relays respectively connected between a row line-wire and a column line-wire, a control reed relay and a common energizing and holding winding for said reed relays, said control reed relay and common winding being serially connected between said principal row control wire and said column control wire and the point of junction of said control reed relay and common winding being connected to said supplementary row control wire, means for selectively applying between said supplementary row control wires and said column control wires energizing signals for energizing the winding and operating the relays of a crosspoint and means for selectively applying between said principal row control wires and said column control wires holding signals for energizing the winding of said crosspoint through its operated control reed relay.

2. A switching network comprising a plurality of cascade-connected matrices, each having rows including linewires, a principal control wire and a supplementary control wire, columns including line-wires and a control wire, and crosspoints each formed by line reed relays respectively connected between a row line-wire and a column line-wire, a control reed relay and a common energizing and holding winding for said reed relays, said control reed relay and common winding being serially connected between said principal row control wire and said column control wire and the point of junction of said control reed relay and common winding being connected to said supplementary row control wire, means for cascade-connecting the line-wires and the control wire of the columns of a matrix respectively to the line-wires and to the principal control wire of the rows of the subsequent matrix, means for selectively applying in time succession between the column control wires of the irst matrix on the one hand and the supplementary row control wires of the successive matrices -on the other hand time-shifted energizing signals for energizing the winding and operating the reed relays of a crosspoint in each matrix, and means for selectively applying between the principal row control wires of the first matrix on the one hand and the column control wires of the last matrix on the other hand holding signals for serially energizing the windings of said crosspoint in each matrix through the operated control reed relay comprised in said crosspoint.

References Cited UNITED STATES PATENTS 7/1924 Richard 335-112 5/1965 Deeg 335-152 

1. A SWITCHING NETWORK COMPRISING MATRICES HAVING ROWS INCLUDING LINE-WIRES, A PRINCIPAL CONTROL WIRE AND A SUPPLEMENTARY CONTROL WIRE, COLUMNS INCLUDING LINEWIRES AND A CONTROL WIRE, AND CROSS-POINTS EACH FORMED BY LINE REED RELAYS RESPECTIVELY CONNECTED BETWEEN A ROW LINE-WIRE AND A COLUMN LINE-WIRE, A CONTROL REED RELAY AND A COMMON ENERGIZING AND HOLDING WINDING FOR SAID REED RELAYS, SAID CONTROL REED RELAY AND COMMON WINDING BEING SERIALLY CONNECTED BETWEEN SAID PRINCIPAL ROW CONTROL WIRE AND SAID COLUMN CONTROL WIRE AND THE POINT OF JUNCTION OF SAID CONTROL REED RELAY AND COMMON WINDING BEING CONNECTED TO SAID SUPPLEMENTARY ROW CONTROL WIRE, MEANS FOR SELECTIVELY APPLYING BETWEEN SAID SUPPLEMENT- 